Stereoscopic display based on holographic information has become more popular. During recording holographic information, two laser beams travelling in different directions, i.e., a reference beam and an object beam, interfere with each other to form an optical interference pattern. The optical interference pattern induces chemical or physical change in the photosensitive recording medium, so that information relevant with an object to be reproduced is recorded in the recording medium. During reproducing holographic information, a reference beam similar with the reference beam for recording is irradiated on the recording medium, so that the reference beam is diffracted by the optical interference pattern in the recording medium to reproduce the object beam, thus reproducing the information.
FIG. 1 is a schematic view illustrating a device for recording and reproducing holographic information. As shown in FIG. 1, a light source 10 like a laser device emits a source beam 11. The source beam 11 is split by a beam splitter 20 into a reference beam 21 and an object beam 22. The reference beam 21 is reflected by a reflecting mirror 30 as a reference beam 31, which irradiates on a photorefractive crystal 40. Besides, the object beam 22 irradiates an object to be reproduced 70 and then is diffusively reflected. The diffusively reflected object beam 72 irradiates the photorefractive crystal 40. The reference beam 31 and the object beam 72 overlap and interfere, so that information relevant with the object to be reproduced 70 is recorded by the photorefractive crystal 40.